In no particular order and with some being related to the desktop-handheld switching while others are more general in nature:
- WiFi issues, especially with 5GHz networks (signal drops regularly)
- fan noise (fan curve ain't great, spinning at full speed 75%+ of the time, high pitched)
- image/resolution scaling issues (mostly when switching between desktop and native Deck mode)
- technical issues with games marked as supported/verified (Dragon Quest XIS e.g. booted with the image being squished to a few pixels in the middle of the screen, making it impossible to navigate the settings to change the display settings from fullscreen to borderless to solve the issue; Horizon Zero Dawn crashed outright on me - twice)
- the trackpads stop working sporadically?!
- the on-screen keyboard doesn't seem to work at all in desktop mode for me, even when using the Deck's own screen and no external monitor
- shader compilation still occuring in-game, even though Steam downloads compiled shader packs with the games already?!
- loading times being surprisingly long sometimes (and adequate other times) (256GB SSD model here, all games installed on the internal memory thus far)
- graphics settings from my PC config being imported onto the Deck (though this might be more on the games than Steam itself), making some games unplayable at first due to higher res and general graphical settings
- Steam Cloud Save synchronization failing regularly for me
- some odd app behaviour (Spotify for instance doesn't properly sync my liked songs across devices, while it works flawlessly on my Android phone and windows PC and even the PS4)
- what I'd call general sluggishness of SteamOS3 and the Deck UI/Gaming Mode (as it's called) in particular, sometimes not reacting to button prompts, menues freezing for a few secs, apps stopping to react (like the appstore e.g.)
- black screen on the Deck itself when booting some games, persisting for anywhere between 30-60 secs; and even closing some titles can lead to something similar
That's all coming to mind right now, with some points that I had actually written down, haha.
Depending on what you're looking for with the Deck, some might be more serious issues than others. Personally I perceive most of them as annoyances, but nothing that would totally break the experience for me. Some edge cases as well that might not even apply to everyone's first experiences with the device.
While it might appear to be a lot at first glance, there's actually more about the thing that I like than what I dislike; as I said in my previous post, I actually do enjoy the Deck quite a bit, and playing Monster Hunter World or Tales of Arise on it for instance has been a blast!
(Also having Persona 4 on a handheld again! <3)